AHS 2012: The Safe Starches Panel

Note: The book has come back to me for copy-editing, that’s why blogging is slow.

The “safe starches” panel turned out to be not about starches, but about carbs. Nobody wanted to contest my assertion that some starchy plants are free of toxins after cooking, so the criticism of starchy foods was solely based on perceived risks from their carb content.

The expectation going in was that Drs. Ron Rosedale and Cate Shanahan would be taking anti-starch/anti-carb positions and that Chris Kresser and myself would take pro-starch/pro-carb positions. But as it turned out, we arrayed ourselves on a spectrum. Ron was resolutely anti-carb, repeating his assertion that we’re all diabetics and intolerant of carbs (see Ron’s summary of the panel here); Cate was more moderate. I supported eating ~30% of calories as carbs, with lower-carb ketogenic dieting as a therapy for certain conditions. Chris took the position that there is little evidence favoring any carb intake over another, and that some cultures have been healthy on carb intakes as high as 85% or more. (See Chris’s summary of his remarks.)

A fair part of the discussion was about longevity and aging, and whether carbs contribute to it. This is a topic that has not been explored much in the Paleo blogosphere, and was the most interesting part of the panel for me.

[Photo from Diana Carr on Facebook.]

My Position: About 30% Carbs is Best

I took an evolutionary perspective. Evolution selected for a carb intake around 30% to 35% of calories. At lower carb intakes, protein is converted to glucose by gluconeogenesis; at higher carb intakes, significant amounts of the excess carbohydrate are converted to fat (not in the liver, but in skeletal muscle and adipose tissue; this is why studies examining lipids exported from the liver show minimal glucose to fat conversion).

If it were equally healthy for the body to have some other glucose supply than the one provided by a carb intake of ~30% of calories, then evolution would not have selected for mechanisms to restore this favored glucose supply by gluconeogenesis or lipogenesis. The body would have accommodated other levels of glucose utilization without trying to alter its glucose supply.

Further, we know that when carb intake is below this natural level, gluconeogenesis does not fully make up the glucose deficit; and when carb intake is above this natural level, lipogenesis does not fully eliminate the glucose surplus. As a result:

  • On high-carb diets, cells/tissues utilize more glucose than in the evolutionarily favored state.
  • On low-carb diets, cells/tissues utilize less glucose than in the evolutionarily favored state.

My thesis is that there are undoubtedly negative effects from over- or under-utilization of glucose by tissues; else evolution wouldn’t be trying to mitigate the over- or under-supply by lipogenesis and gluconeogenesis. And we know at the extremes that negative effects do occur:

  • On very high-carb diets, eg macrobiotic diets, lipid deficiencies appear, reflected in reduced serum cholesterol, impaired immunity, and often mood disorders. We’ve blogged about the effects of lipid-deficient diets in infants.
  • On very low-carb diets, we often see deficient production of mucus and tears due to downregulation of mucin production. We’ve blogged about this.

On less extreme divergences of carb intake from the evolutionary norm, there are no obvious acute effects, but the possibility exists of long-term negative effects.

Ron’s Misunderstanding of My View

Ron Rosedale seems to have misunderstood my argument. In his “A Conclusion to the Safe Starch Debate,” Ron asserts that I am concerned only with blood glucose levels. No, not at all: I am concerned specifically NOT with blood glucose levels but with tissue glucose utilization.

Perhaps a metaphor may help. Imagine an oil well facility connected by pipeline to an oil-burning power-plant. Suppose that it is essential to always maintain a certain pressure of oil in the pipeline, or the pipeline will suffer damage. When the oil wells produce more oil – say, because a new well has become a gusher – the power-plant burns more oil in order to maintain the proper pipeline pressure. When the oil wells produce less oil – say, they’re down for maintenance – the power-plant uses less oil. Always the pipeline has the same amount of oil.

Even though the pipeline always has the same amount of oil and the same oil pressure, that doesn’t mean that it doesn’t matter how much oil is entering the pipeline. The whole complex of wells-pipeline-powerplant may work best and be most robust to trouble if a normal amount of oil is being produced at the well end and a normal amount is being consumed at the powerplant end. Extreme levels of oil production may strain the powerplant’s ability to operate – insufficient oil may shut it down, and excess oil may burn it up or strain its facilities.

In the same way, eating too few or too many carbs will not affect the levels of glucose in the blood – these must be maintained above 60 mg/dl if glucose is to enter the brain which is essential for life even under ketosis – but may strain or stress our tissues which must downregulate or upregulate their utilization of glucose to match the flux of carbs into the body.

Cate Shanahan’s Experience

Cate Shanahan mostly discussed her experiences recommending a low-carb diet to her patients. She says that none of her patients have reported glucose deficiency symptoms, such as dry eyes. For me this mystery was cleared up when she said that she recommends her patients get 70 g of carbs daily. I and others have found that 50 g of starch is a sort of magic level that usually eliminates acute symptoms like dry eyes.  So Cate appears to be recommending a level of carb intake that minimizes the risk of acute symptoms.

It wouldn’t surprise me if most of her patients are eating much more than 70 g. We know the food reward system strongly rewards carb consumption, so that nearly every culture on earth eats at least 45% carbs by calories. Quite possibly most of her patients are eating PHD levels, 100 g to 200 g.

Is there a counter-argument to my evolution based view?

To date, I’ve seen two counter-arguments:

(1)   From the low-carb side, chiefly Ron Rosedale: Evolution didn’t optimize for longevity but for fertility, and we want longevity, therefore we should resist adopting the evolutionarily favored diet.

(2)   From the high-carb side, voiced to some degree by Chris Kresser in the panel: Why isn’t a negative effect of high or low carb intakes apparent in epidemiological data? There seem to be healthy long-lived societies with high carb intakes.

These seem to me to be the interesting issues coming out of the safe starch debate. I will only give brief answers here.

Contra Ron: Very low-carb for longevity

I have two replies to Ron’s argument that very low-carb diets will maximize longevity.

First, evolution DID select for human longevity. The maximum human lifespan is double that of chimps and gorillas. Humans have mitochondrial membranes selected for extreme longevity. Both of these points are discussed in our new Scribner edition. This should give us confidence that the 30% carb intake selected for by evolution may well be the carb intake that maximizes longevity. I believe it is.

Second, Ron’s arguments are based on Cynthia Kenyon’s experiments in the nematode worm C elegans, in which she found that mutations to Daf-2, which is an insulin-like receptor in C elegans, extended maximum lifespan. Cynthia Kenyon famously switched to a low-carb diet after these experiments. However:

  • Humans have multiple genes which are analogs to Daf-2, including insulin-like growth factor 1 as well as insulin, and IGF-1 appears to be more strongly related to longevity than insulin in humans. More significantly, insulin actually antagonizes Daf-2 in worms, inhibiting its signaling; calling into question whether Daf-2 biology can tell us anything about the effects of insulin signaling in humans.
  • More importantly, the mutations to Daf-2 extend maximum lifespan in the laboratory, but they shorten expected lifespan under natural environmental conditions. When Daf-2 mutant worms are placed in the soil, they live shorter lives.

I made the second point during the panel. Here is the reference:

C. elegans mutants that live twice as long as wild-type worms in laboratory conditions typically die sooner than wild-type worms in a natural soil. These results indicate that conclusions regarding extended longevity drawn from standard laboratory assays may not extend to animals in their native environment. [1]

Even if Daf-2 mutant worms were an adequate model of human longevity, we would have to confront the issue of the robustness of health and longevity to stressors such as infections.

The death of Roy Walford, calorie restriction practioner and longevity guru, at age 79 from ALS – a disease that is promoted by fasting and calorie restriction – should warn us about the risks of extreme diets. There are pathogens that can exploit every human environment. “Feed a cold, starve a fever”; for different germs you may need different diets.

Evolution selected for a moderate carb intake because it makes us robust against a wide range of threats. Carb restriction, like calorie restriction, might protect us from some threats but expose us to others. In our natural, free-living situation, we’ll come up against every threat sooner or later. Just because an extreme diet may have the potential to extend our lifespan does not mean that it will. It may reduce our expected lifespan by making us vulnerable to new threats. The safest course, I think, is to follow evolution’s guiding hand.

What Does Experience on High-Carb Diets Tell Us?

Chris Kresser cited a number of healthy high-carb cultures, and noted that Okinawans became the world’s longest-lived culture after being forced to an 85% carb diet during World War II and its aftermath. Stephan Guyenet cites this as a telling point of the debate:

One of the most surreal moments happened right after Kresser brought up the Okinawans, the longest-lived culture and one of the healthiest in the world, and cited a paper showing that their traditional diet was ~85 percent carbohydrate, mostly from sweet potatoes.  Shanahan and Rosedale decided, based on thin air, that the Okinawans actually didn’t eat much carbohydrate, and Shanahan even went so far as to say “I don’t believe you”, even though Kresser was staring right at the citation on his laptop!  This is the kind of head-in-the-sand approach to science that we need to move beyond in the ancestral community.

The source for an Okinawan diet of 85% carbs was published in 1949, and the data was gathered during the post-World War II US occupation. This was a time of desperate poverty, and indeed followed years of poverty and famine during the Great Depression and World War II. Let’s not forget that the Chinese civil war was taking place during this period, and the Korean War was about to begin. Shou-Ching’s parents lived through this period, in China and Korea, and it was a time of starvation for them and for many others in east Asia.

All deeply impoverished people around the world eat high-carb diets, because carb-rich plants are the most readily available “fallback foods” in the natural environment and the cheapest calories available on the market. As soon as animal foods become available, cultures around the world migrate to 50% carb diets.

We have testimony from Okinawans who lived at that time telling us how difficult it was to obtain food. Their diet was severely calorie-restricted. I recall one Okinawan centenarian on television stating that they ate many kilograms of vegetables each day, simply because there was nothing else. (It rather resembled the Terry Wahls diet – very micronutrient rich.)

Then, decades later, the Okinawans become noted for their longevity. What produced the longevity – the carbs or the calorie restriction? Most likely the calorie restriction and high levels of nutrition were more important than the carb-to-fat ratio.

Food quality is also a factor. As readers of our book know, we think traditional Pacific islander diets are the healthiest in the world – composed of safe starches, coconut, and fish, very low in sugar and omega-6 fats. Whatever the carb fraction, such diets are healthier than the American diet. If there is a place in the world to survive a starvation diet of foraged and locally grown foods, it is a Pacific island.

My view: It was silly of the anti-carb panelists to refuse to credit the Okinawan data, but it is also misleading to say that the “traditional diet” of Okinawans is 85% carb based on data from a period of starvation and food scarcity.

As I noted in the panel, when people are able to eat as many calories as they wish, carb intake is generally anti-correlated with longevity at a population level: higher carb intake is associated with shorter expected lifespan. This is mainly due to the correlation of higher carb intake with poverty, but it occurs even within smaller samples of countries at similar income levels. For instance, among the European countries, higher carb intake is associated with shorter lifespan.

As I stated in the panel, this is extremely weak evidence for an effect of carbs; there are many confounding factors and population-level data cannot sort these out (the “ecological fallacy”).

Personally, I give more credence to data on centenarian diets. Few supercentenarians eat high-carb diets, so carbs may indeed reduce maximum lifespan, though eating a high-carb diet certainly doesn’t prevent people from becoming centenarians. (Supercentenarians live to 110.)

How carbs affect appetite may be more important than specific biological effects of glucose (or insulin). As the Simpson & Raubenheimer “protein leverage hypothesis” data show, in rodents higher carb diets are associated with higher calorie intake. Perhaps something similar occurs in humans. We know that energy excess and calorie restriction are major factors in longevity.

In short: I personally think that the relationship of carbs to longevity is U-shaped, with longest expected lifespans at a 30% carb intake; and I think available data is consistent with this. But I think the influence of carbs on longevity is small compared to other factors.


I was concerned going in that the panel would merely re-hash old arguments. I think the anti-carb arguments were, for the most part, familiar and weak; but I think the discussion took us to interesting places. I think the issue of the healthfulness of very high-carb diets, and the data from cultures like Okinawans, is a very interesting topic; and I think the issues of aging and longevity are quite interesting. I enjoyed the panel.

There are some health conditions which benefit from low-carb eating. I am grateful to our moderator, Jimmy Moore, for allowing me to enumerate some of the health conditions that have benefited from the ketogenic version of the Perfect Health Diet.

All in all, I think it was a good discussion but if it is to continue either the very low carb advocates will need to come up with better arguments and better evidence, or the topic will have to shift to exploring the merits of high-carb diets – a topic which the ancestral community hasn’t spent much time discussing.


[1] Van Voorhies WA, Fuchs J, Thomas S. The longevity of Caenorhabditis elegans in soil. Biol Lett. 2005 Jun 22;1(2):247-9. http://pmid.us/17148178.

Leave a comment ?


  1. Hey Paul,

    Most of the debate around safe starches seems to be centered around what happens in our bloodstream – but I haven’t seen much (if any) discussion about what our gut microflora should be eating to create a healthy immune system for their hosts (us). Thoughts?


    • Great question, Tim. I think low fructose and low omega-6 are most important. Starches (via resistant starch) and fruits/vegetables (soluble fiber) are helpful. Saturated fats are helpful. Not too much protein is helpful. Not too much iron is helpful.

      • Well it ain’t sugar! Carbs SUPPRESS immunity for 2 to 5 HOURS, see chart showing effect of 6 different sugars & starches on leukocyte activity & levels, and references in footnotes. http://goo.gl/c23Qt and http://goo.gl/eL0Q9

        • Hi cancerclasses, the study in that first link uses quite a lot of carbs in one sitting, and the preferred carb around here (starch) only suppressed the immune system minimally. Furthermore, I don’t think PHDers will eat 100g of starch without some fat or acid to slow down the uptake.

          So while I agree that drinking a super size coke seems to be an extremely bad idea for immune function, I’m not seeing anything that keeps me from eating starch from whole foods as part of a meal, or even simply a few pieces of fruit.

          • Actually, thinking about it some more, could it be that the reduced leukocyte index simply shows that gut flora activity is up due to excess food making it into the gut, and the immune system reacting to that?
            I have no idea what the leukocyte index really means.

  2. Paul,

    You have a refreshing tone and argument strategy. In general I would say people’s positions are too adamant due to obvious unclear evidence.

    One thing is that I am definitely tired of hearing about long-lived populations on high carb diets. There are simply too many other variables to consider, and the number of populations eating that way is much greater.

    Higher fat diets seem to give more favorable blood lipids and hormone panels, and although this is not definitive, we have to generalize from somewhere. Tafur and Dobromylskyj have presented good arguments in support of using fatty acids and/or ketones vs glucose.

    The huge range of condition benefits from ketogenic dieting warrants more investigation I think, despite some anecdotes of negative experiences. For these people, including you I suppose, it is difficult to for sure say that more carbohydrate was the sole solution. Mineral balances/intakes, vitamin A, choline, amino acid balance, etc may all be factors.

    • Hi John,

      Yes, in general avoiding a carb excess is good for CVD risk factors. I don’t see much improvement from going below 30% carbs however.

      In my case I don’t intend to do the VLC experiment again. It’s true my nutrition was poor at the time, but I think I needed the carbs.

  3. Makes me wonder if it would be smart to throw in high and low carb days just in case, like a few times per month, to cause mild stress to both systems.

  4. There is a bias in this “evolutionary” view of things.

    You start with the idea that our evolution favored an optimal ratio for carbs, giving us both gluconeogenesis and lipogenesis to compensate around this 30% carb you think is optimal. But until now there never was anywhere a place where a steady ratio of nutrients was found all year round.

    So maybe this apparent “30% optimal glucide” is just an ideal middle ground from where it’s more efficient for the organism to compensate in both direction as need apears. And that can not even say that it’s the best ratio to aim.

    Consider that it could be that the ideal ratio is (say) 60% glucose, but the mecanism is centered around 30% just because it’s more efficient (between meals, etc…) to compensate for carb/fat burning from this point.

    • Hi Renaud,

      It’s true we had to be adapted to significant variability in carb availability. This is, I think, why we don’t easily see obvious health effects from low or high-carb diets. We evolved an ability to cope with such diets in the short-term, so it takes a very long term to see an effect.

      But I don’t see how the ideal ratio could be 60% if, when we eat 60%, some of the glucose is eliminated by lipogenesis.

      • Perhaps because for some reason it’s best to store some lipids instead of burning all the glucose, as soon as glycogen stores are repleted. Not only this can save tomorow if food become scarse, but that can help going through low level activity where glucose oxydation is not involved… it’s the best of “eat one fuel, get both and use whatever is best in context”.

        If the body burn 30% glucose, does it imply that it’s the best to feed it 30% glucose ? I’m really not sure of this !

        Consider an hybrid car. Maybe it’s built to behave “optimaly” at 70% electricty and 30% gas. But that DO NOT mean you have 70% fuel tank and 30% battery… in fact, in use optimum is to just fill the fuel tank (but a few charging is not forbidend) : you are allways sure to start going ! Battery is charged while running on gas, and used when needed. So paradoxicaly gas is the best fuel even if the car, “optimaly”, mostly use electicity.

        • sorry i mean : 30% fuel tank and 70% battery

        • I understand your argument, but I don’t think it works.

          First, there is the issue that glycogen storage is limited, but the lipogenesis/gluconeogenesis pattern is consistent no matter how long a high or low carb diet is sustained. So limits to the size of the fuel tank (or battery storage) don’t affect the issue.

          Second, if lipogenesis on a high-carb diet is sacrificing present utility (which would have been maximized by using the carbs) in order to protect against a future famine by storing fat, then lipogenesis should be downregulated in obesity. It’s not.

          The argument fares even worse from the low-carb angle. Then it would be that 10% carb is optimal, but the body sacrifices protein to make more glucose — why? Clearly losing protein is costly.

          • I admit i’m mostly biased toward more carbs 😉 I do not have a clear idea of what is the ideal ratio, but I allways try to challenge what seems too obvious. In particular when complex living organism is involved.

            Limited size of respective fuel tanks is probably mostly a reflect of relative (external) fuel availlabiliy. If carb is easy to find (and/or you burn relatively few of it), you do not need a big tank. When carbs are not availlabe, you get to the fat/meat combo, wich easily provide the few required glucose. And you can also deal with nothing at all for a while. So, you never need a big carb tank.

            Maybe lipogenesis on a high-carb diet is not sacrificing present utility! That would be the case if the purpose of fat storage was restricted to famine, but it is not : we are an efficient, intelligent, dual fuel engine day in and day out!

            Regarding obesity, it’a also a complex subject and i know very little about it. But i’m inclined to think that downregulating lipogenesis in obesity would only make sense if, in the milieu of evolution, durable high food availlability was the norm.

      • note : i don’t say 60% glucose is optimal. Maybe it’s 10 %. That’s not the point.

      • Aaron (HaloTeK)

        “But I don’t see how the ideal ratio could be 60% if, when we eat 60%, some of the glucose is eliminated by lipogenesis”

        Well, what if fat produced by our bodies is optimal in that it is exactly what our body wants. When we eat fat — we may eat oxidized fat or fat that has ratios away from what our body would make. Hense, I can see scenarios where DNL might be better than a higher fat intake (of course we need to eat some)

  5. Paul
    You touched on a point that interests me greatly. How accurately does BG level measured by (say) figer-stick meter reflect the flux of glucose and how uniform is the actual BG concentration in the body. My personal measurements indicated very large (25% in one case and 100% in the other, on a handful of tests) variations in different body parts (compared to my standard abdomen test site). Anomalous readings only occurred rarely and under unusual condition, later I could not repeat them. I took steps at the time to account for possible instrument errors ie changed strips, used test solution, changed meters, checked for unusual readings of the original test setup at a later time but normal conditions. I have seen a review of significant BG variations under insulin perturbations in animal models (but can’t find the link). There is nothing unusual with my BG. My annual (venous) BG test averages 4.6-4.9 mm/L and is only slightly lower than my own tests. I am trying to sort this because I definitely experience better mood and cognitive function at lower (<150gm) glucose) but a little worse foot neuropathology (mild) at the lower end. These observations suggest to me some variation in body glucose partition. I do not yet dare increase my glucose as I am experiencing a continuing and improbable improvement in (decades long) periodontal gum disease and other connective tissues. My diet experiment is still young (2 years) but both my weight (BMI 23) and calorie intake (2200-2400) have been essentially constant for the last 6 months. I owe my experiments to your first book, for which I am very appreciative.

    • Hi Morris,

      It’s quite puzzling to me too. I’m not sure what would cause that. In Raynaud’s the extremities do get unusually cold compared to the rest of the body, and thyroid hormone regulates macronutrient entry to cells, so I guess I can believe that something like this can happen, but I don’t know what could cause it.

      Have you tried vitamin C supplementation?

  6. A question: in your book, you talk about Starches being 50-150 grams of starches, but also say that most vegetables are fermented into short chain fatty acids. How does the diet differ if it is 150 grams of vegetable carbs, or one that is 100 starch carbs and 50 vegetable carbs?

    • Hi Amanda,

      Fiber is fermented into short chain fatty acids. Vegetables have both sugar and fiber.

      Most vegetables are pretty low in carbs, and some glucose is spent in digestion, so we recommend getting some starches in addition to the vegetables to ensure a healthy glucose status.

  7. It was disappointing for me that the carb issue was again a hot debate at AHS 2012. I’m curious to see a reference that significant DNL occurs in adipose and skeletal muscle tissue in properly controlled studies. To use super centenarians as evidence reeks to me of confirmation error, narrative, and a high likelihood of silent evidence. I’m glad at least yourself and moreso Kresser are reporting the benefits of carbohydrate consumption.

    • Hi Gabriel,

      Citations on DNL are in the new edition of the book.

      • Lol, you’re trying to up sell me now Paul!?

        • Heh. It’s worth it Gabriel!

          • My issue would be that DNL is of no consequence regarding weight loss when calories do not exceed daily energy expenditure. I’m also curious as to your thoughts on the finding that increased adipose tissue DNL is associated with improved fasting glucose, glucose tolerance, and insulin sensitivity mediated through palmitoleate and perhaps other unknown factors. It is safe to say that overconsuming either fat or carbohydrate would lead to metabolic dysregulation.

  8. Paul,

    Do you have a cite for the association between CR and ALS? Dr. Walford himself seemed to chalk up the ALS to toxin exposure in the Biosphere project. He actually credits his CR to extending his life with ALS to a very respectable 79.

    Given what isn’t known about ALS, the line ‘ a disease that is promoted by fasting and calorie restriction’ seems awfully strong.

  9. I appreciate your thoughtful and evenhanded discussion in this blog. You have made some fine points especially about the Okinawans.

    However, I think that you would have an extremely hard time convincing most, if any, biologists that evolution selects positively for post-reproductive longevity outside of reproductive success or even is capable of doing so. Nature is selecting for genomic survival, and the only purpose of the body, the soma, is to aid in this accomplishment and thus becomes very expendable.

    Even diseases such as obesity and insulin resistance can be viewed as mechanisms to help ensure reproductive success while increasing our post-reproductive demise (antagonistic pleiotropy).

    The reason that nature has apparently conferred a greater lifespan in humans than chimps, is because our infants are so helpless. What I said was that nature selects for reproductive success, and that includes allowing parenting and parents (and even grandparents) a long enough lifespan to care for their young “until they can stand on their own 2 feet”, to quote myself. It does not select for post reproductive longevity.

    The fact that many species whose actual existence has been selected for hundreds of millions of years longer than humans, such as cockroaches, who’s lifespans are still measured in months and likely have not increased much if any over the years, is just testimony to the fact that it is not overall lifespan that is selected for. Furthermore, it would not seem reasonable that humans have a different set of rules than the rest of nature.

    As far as aging, there are hundreds, perhaps thousands, of articles that link the insulin pathway to aging and age-related diseases such as cancer, diabetes, heart disease, etc. in not just worms but many diverse species including humans, higher insulin signaling greatly increasing risk of disease and accelerating aging. I don’t think that you will find a way around this in your arguments. I will agree that IGF-I is particularly important in this regard but it must be recognized that insulin and IGF are cousins (“insulin-like growth factor” is not a misnomer) and cross react with the same receptors. This is one reason why I believe high insulin is now so often associated with increasing risk of many different cancers. Though I have talked about all this many years ago for many years (see “Insulin and its Metabolic Effects”), perhaps when I have time an update is in order.

    And then, even more importantly for us humans, there is leptin…

    • Thanks, Ron.

      I think the longevity and evolution issues are fascinating. But I think selection for longevity in humans is probably related to the importance of cultural preservation in technologically sophisticated social groups, and cultural transmission from grandparents to children.

      One thing I’ve learned in 12+ years of doing biology is that it’s never a good idea to try to guess what signaling pathways do. You have to directly observe them. And the long term effects of carb restriction have not been observed.

    • Aaron (HaloTeK)

      Ron, I appreciate all your contributions to nutrition discussions over the years.

      What I would like to see more of though is more complete date on how you seem to relate the metabolisms of worms and lower animal to humans. My bent in nutrition has always been to maximize longevity.

      Lower carb diets always seem to mess up my own stress axis even after adaptation — I’m sure this has occurred in other individuals as well. Also, there is some literature to suggest that increasing CO2 within our system is beneficial to keeping our stress axis and metabolisms running clean. I’m more in the Peat camp that glucose is a cleaner burning fuel. Unlike fat metabolism that spits out all kinds of free radicals. You have mitochondrial free radicals vs what you call an increase in insulin <— but insulin doesn't always act as I have seem people talk about it.

      Lastly — you say your diet would be optimal for almost all creatures. Like I have posted on Stephan's site — would you say that your diet would be optimal for a mammal such as a whale if you could feed it the amount of calories required — would that beat of the longevity it has from a diet full of krill <— I am also assuming it would be in warmer waters (obviously you need layers of omega 3 if you are in cold waters)

      • Hi Aaron,

        glucose is a cleaner burning fuel. Unlike fat metabolism that spits out all kinds of free radicals.

        Eh? It was my understanding that it was quite the reverse? Anyone?

          • Aaron (halotek)

            Paul, if you ever get the time to post on it — I and others would be all ears.

            I know you have addressed Peat in the past, but if you put a lot of his fructose ideas aside his ideas on the difference between what fats and carbs do to cellular system is fascinating — It’s really interesting to see what is going on at the mitochondrial level when comparing fats and carbs.

  10. I agree with Paul and also it is important how much glucose whe need in different stage of our life. Like when I was pregnant and breastfed I have found that I really need lots of sugarry fruit like grapes pear banana to make up my energy level. I can say that I craved these fruits a lot and I could not eat any green veggies that time (I would throw up) Now I eat lots of veggies little less fruit (2-3 pieces mainly berries and citrus) but still need starch like butternut sometimes even daily. When I ate higher fat diet less carb I felt slugish not good at all. I also have to say dispite I eat about at least 30-35% of carb I am very lean skinny woman and never have problem with weight.

    • Thanks for sharing this experience Michaela ! Do you mean you try to follow PHD ? Or do you eat something like PHD, eating starch coming more from starchy veggies (like winter squashes or sugary plants ?) or do you allow coming into your plate some safe starches, as Paul recommend to do ? Thanks, best, Maya.

  11. Paul,

    Does your carb intake recommendation change for athletes?

    • Hi Alex,

      Athletes are complex. Intermittency becomes important – overfeeding after intense workouts, underfeeding after restful workouts. Generally carb loading before an event is helpful. For endurance athletes lower carb brings helpful training adaptations, for sprint athletes higher carb brings beneficial adaptations.

      • Hey Paul, so for athletes that are trying to gain weight but feel groggy from eating carbs during the day, do you still recommend to overfeed on saturated and monounsaturated fats throughout the day, then have a huge amount of starches (300 grams of carbs worth) post workout?

  12. Paul, can you give more info why underfeeding after “restful” workouts would be optimal? And can you define what restful here means?

    Generally I have noticed greater strength gains when feedimg more safe starches during the intense workout days.

    It is fascinating to follow yoyr debate on this matter.

    Greets from Helsinki, Finland (I work as a physician and treat patients with modified paleo approach close to perfect healtj diet)

    • If you overfeed every day, you’ll add both fat mass and muscle mass.

      Overfeeding after workouts maximizes the stimulus to muscle growth, whereas underfeeding on rest days will tend to deplete fat mass. So you get muscle growth but remain lean.

      Restful workouts means that rest days shouldn’t be days of total rest, unless you’re unhealthy or really out of shape. For anyone reasonably athletic, they should be days of activity, but not strenuous activity. The activity should be light and refreshing, not tiring. Yoga, tai chi, jogging for a runner, play, hiking, those are examples of restful activity.

      • Great answer, got it 🙂

        I workout 3-4 times per week heavy liftin (+ intensive intervals). On rest days I usually walk, stretch, foam roll etc.; also some qi-qong. The term “restful workout” was new to me.

  13. Welcome back Paul,
    It’s so good to see you blogging again! Glad to hear that the book is largely ” in the can” and that you will soon write about your newest thoughts on supplementation. I’m tremendously grateful for your hard work in this area.

    I bought the new book months ago and only wish I did not have to wait for December.

    Warmest wishes

  14. Just looking at what Dr. Rosedale said above..

    “As far as aging, there are hundreds, perhaps thousands, of articles that link the insulin pathway to aging and age-related diseases such as cancer, diabetes, heart disease, etc. in not just worms but many diverse species including humans, higher insulin signaling greatly increasing risk of disease and accelerating aging. I don’t think that you will find a way around this in your arguments. I will agree that IGF-I is particularly important in this regard but it must be recognized that insulin and IGF are cousins (“insulin-like growth factor” is not a misnomer) and cross react with the same receptors. This is one reason why I believe high insulin is now so often associated with increasing risk of many different cancers. Though I have talked about all this many years ago for many years (see “Insulin and its Metabolic Effects”), perhaps when I have time an update is in order.”

    I’ve skimmed through some research literature in regards to this topic and have noticed that a few papers have mentioned that it is not the pathways themselves but rather degeneration of the pathways which they claim to affect aging.

    Is it possible that the body’s ability to use the insulin pathways is related to the amount of oxidative stress and not the other way around? Rather, aging affects the body’s ability to metabolize glucose not glucose ages the body.

    This theory still has problems reconciling with anti-aging caused by blocking Insulin pathways in fruit flies and the such. It’s also possible that blocking insulin pathways can be used as a temporary mean to allow extension of the organism’s life but in the long run there are other effects from running a ketogenic diet that are only observable in mammals and the likes.

    I’m very poorly informed in regards to the pathways themselves, just a university student trying to learn!

  15. Great explenation. I have seen great results using this approach incorporating the Leangains model but modified some:

    I fast 16-20 hours a day (feeding window 4-8 hours).
    Workout days, lifting (3 days a week)I over feed some and use the post fasted workout to add in my safe starches. I have a large meal that includes sweet potatoes, roots, berries and meat. Later meals are vegetables, perhaps berries and meats and fats. ( lots of seafood included ).
    Rest days are active skill training sessions and movements mainly like you stated, active rest. These days are very low carb and a bit under feeding with meats, some little vegetables and fats like coconut, bacon, fish etc.

    Seems like this way I stay pretty low carb using fats and ketones as fuel while also flying in and makig use of healthy carbs where needed and insulin is ready….

    What do you think of this approach. Looking at it from a healthy approach to life-long fitness, health and active long life-style.

    Great to see your posts again……

    • Hi Dan,

      Yes, that’s a healthy approach. I don’t think it’s necessary to limit carbs so much — you would probably benefit from more carbs — but if that’s what you like that’s great. I think the daily fasting gives you all the ketosis you need.

      • Aaron (HaloTeK)

        Quick question — if your liver is pretty much full of glycogen, how many hours do you need to fully deplete it? Any studies out there on it. I know I’ve read figures like around 24 hours but I don’t wanna guess.

  16. i agree that 85% carb was poverty food during 1949 (which is not at all representative of the traditional diet)

    i agree that the Asian diet is closer to 50% C.

    do they also get more sun? Kitavan probably do.

    @ Morris,

    do you find your finger tip BG higher or lower than other places? that is interesting. (i have mild Raynauld)


  17. Hi Paul:
    Let us not forget genetics. I am not a Kitavan, and if anyone noticed the difference in muscularity between Asian and non Asian athletes, it at least to me appeared to be striking. So, it may be that Kitavans are genetically better able to handle a high carb than someone like me of European ancestry(may be potatoes better for me than rice- non Irish European ancestry, ha, ha!)
    In the 21st century with various tests available such as A1C,NMR,etc I think we can do better than just looking at evolution and saying this is the appropriate diet. One size does not fit all, and for each to find what works for them. I eat little carbs: some potatoes or rice, some fruit when i like and sometimes non at all. I also, believe that as we age our ability to handle carbs diminishes although i have not seen any supportive data on this. Thanks for your great work- and I will be purchasing the 2nd ed of your book(already have first one) when it comes out.

    • Hi Steve,

      I would phrase it as “our ability to handle an excess of carbs diminishes as we get older,” but I think that is true. Diabetes rates shoot up after age 65, and obesity rates go down. This happens in mice when adipose cells cease to take in energy … which diminishes glycemic control.

      Thanks for your support!

      Best, Paul

      • Hi Paul,

        So, if you think that “our ability to handle excess of carbs diminishes as we get older”, do you think it can also concerns “carbs” eaten without excess ? And would you intend to go further in this debate for a special PHD for the older ?Thanks,Blessings,Maya

  18. Ancestral Health Part 2 : Dominic Munnelly Personal Training - pingback on August 20, 2012 at 8:58 am
  19. @pam
    No I have not seen a consistent difference between abdominal and finger-tip FBG but then I have not done enough trials. There is a lot of noise in my FBG readings, about +/- 15% over a period of 12-15 months, much less over shorter periods. Abbot’s glucose meter instructions say to avoid finger-tip samples if hypoglycemic, so variations must not be uncommon. I have mild neuropathy in feet (very cold when snow skiing and small loss of feeling in soles at worst case) and in hands (tingling fingers after 20-30 minutes of aggressive bicycle riding ie tight grip on handlebars. My observations suggest to me that BG measurement do not accurately reflect the total glucose production (see Paul’s analogy to pipeline pressure) or glucose distribution in the body. My case is that I have a lot of worn parts (age) but not anything really broken, so I experience aging biomarker fluctuations (positive & negative) which can inform my experiments. You, like me, are lean and by inference relatively healthy and may find that careful observations are very useful.

  20. Hi Steve & Paul
    There is a suggestion (eg Nick Lane & others) that senescent cells rely more on glycolysis possibly due to diminished mitochondrial function. The aging body may then overproduce glucose to satisfy that need in the senescent cells but in the process harm the relatively healthy cells. My experience suggests at least superficially, such a process i.e. variable partition of glucose. Paul’s analogy to pipeline pressure is very apt here. In my case microbes are also involved (periodontal gum disease) and may also contribute to local glucose consumption e.g. in other connective tissue. There is no doubt much more to this aging idea but blaming glucose per se does not seem sufficient.

  21. Paul, this is a really great article. I would only correct your statement that ALS is ‘promoted’ by calorie restriction. It seems that you meant to say that calorie restriction accelerates the progression of the disease, which I think is more accurate because we really don’t know what promotes ALS exactly.

    Calorie restriction is a ambiguous thing, I think, that needs a bit more clarification in general. There are degrees obviously, and there is also differences in kind.

    I think absolute calorie restriction is a powerful tool initially, and likewise, probably not all that healthy if macro and micronutrient ratio are not optimized aka the twinkie, doritos, etc. diets…I think over a year you might find that those people may develop serious problems, although initially they do well, whereas a more more nutrient dense diet, even if significantly calorie restricted might produce a much more beneficial result over the long term.

    Any thoughts?

    • Fair enough. Accelerates the progress of ALS may be more accurate.

      I think being well nourished is important. You can only reduce calories so far without becoming malnourished. But my main belief is that intermittent calorie restriction delivers all the benefits of continuous calorie restriction with fewer risks.

      • I agree. Intermittent over fasting, quality of food over actual amount restricted, and being well nourished is key.

        I am in definite agreement there…I consider being well nourished through consuming nutrient dense and toxin free free foods (which allow the nutrients to actually be utilized) the ‘hidden side’ of a successful low carb approach, as I think you do as well.

        I know you had mentioned that you consider micronutrient deficiencies an important factor in obesity, and they may even be a driving force for obesity. I agree with this view as well, Paul.

        Grains, sugar, processed foods are generally provide calorie density in the diet without nutrient content.

        As always, keep up the good work.

  22. So if I want to gain 10 pounds, would increasing carb intake be a good way to do that?

  23. Hi Paul – I have enjoyed following this starch/carb optimal macronutrient debate immensely, both in your and others’ blogs and books, and at and after the recent forum. I am extremely grateful that you and several other leading participants in this community maintain such open-minded attitudes to differing viewpoints and make obvious effort to avoid entrenched positions and dogmatism. This is obviously a great boon to the challenge of continuing to advance the knowledge.

    In this context, I note with interest some evolution in your own views on optimal range for dietary carbs. In the first edition of your book you recommend a range of 200 to 600 carb calories, with a norm of 400, so on 2000kcal/day, 10%-20%-30%. Your discussion there was based on usage (energy metabolic plus structural or other functional uses) and storage (cellular and serum). I like the approach of starting with basic needs, but of course to translate this back to recommended dietary intake one must factor in assumptions of turnover rates of stored or structural carbohydrates, as well as conversions to/from other macronutrient forms, which can all get complicated.

    I have not reviewed all of the recent debate, but arguments you put forth in the blogpost above are based on a simple observation that we seem to have evolved opposing mechanisms of gluconeogenesis and lipogenesis which center around a dietary carb intake of 30%. I like this approach as well, though it begs the question of whether optimal dietary intake is that which minimally invokes these two conversion mechanisms, as well as the questions you have addressed regarding whether our species’s evolutionary goals coincide with our individual optimal dietary goals (longevity vs reproductive advantage, etc.).

    These two different approaches to the basic optimal diet question are clearly both valuable, and I am sure that as our understanding advances we ought to be better able to reconcile one to the other. For now, I’d be grateful if you could comment on how your own conclusions may have evolved somewhat over the last year or two. Also, wondering if the macronutrient section of the new book (preordered and eagerly awaited here!) has been significantly revised.

    Thanks a lot

    • Hi MH,

      Our macronutrient recommendations haven’t changed much, but we elaborate on them a great deal. I’d say we’re a bit more sympathetic to slightly more carbs, headed more toward 30% carbs from 20%, but that’s not a big difference.

      The micronutrient recommendations and food-cooking recommendations have changed more than the macronutrients.

      Also, we’ve added more material on immunity and lifestyle, and on causes of obesity; and a number of reader stories.

      Overall, the book is about 50% longer.

      • Are you more lenient with respect to fructose in your new leaning, or are you still just as firm that the 30% should all come from glucose?

        • We recommend about 15% of it from fructose, 85% from glucose. That allows a fair amount (1-2 lb) of sugary plants (fruits, vegetables, carrots, beets). But doesn’t leave room for added sugar.

          • Awesome! I plow through 2800kcal a day so that gives me 210g carbs of which 63g can be sucrose. That’s two cans of Coke! 😉

            Did I tell you I love custard? Egg yolks + cream + some sugar and flavorings… I just made it with cardamom, so good…

            PS: just kidding about the coke – things that sweet make me cringe nowadays.

  24. Hi Paul,

    I´ve thoroughly enjoyed your blog and your responses to others´ comments.

    In similar vein to taking advantage of the carb refeeds in post workout windows 2-4 per week and low carb eating on restful activity days. Would a once a week carb refeed and calorie spiking (Cyclic Ketogenic Diet) be a good idea for either athletic or longevity goal?

    I´ve heard other prominent Paleo advocates say throwing carbs at least once 2-5 days is a good idea for maintaining healthy thyroid_hormonal status?



    • I do think intermittent calorie spiking is a good idea, but the increased calories should follow every intense workout, so rather than once a week it should be timed around your workout schedule. If you workout twice a week, overfeed twice a week.

      The overfeeding doesn’t need to be especially high in carbs, it can be a bit higher, say 40% carbs. I would say a bigger issue is that most ketogenic diets are too low in carbs, so the rest days may be too low carb.

  25. Hi Paul,
    I’ve been doing a very low carb diet for many years, and according to your book it has been way too low! I have developed low T3, hypoglycemia, anemia and so on.

    I’ve have started to see a holistic DO which has also diagnosed me with low functioning adrenals. He wants to treat me with an extended release T3 medication to se if he can “reset” my thyroid. Do you think this will be helpful? Also I was wondering what you would reccomend my amount of carbs a day should be while in this condition. It will be hard for me to eat more carbs as I feel like I have been brainwashed into thinking they are so bad!!

    Thank you for your amazing book and all of the research you have poured into it!
    Looking forward to more publications!!



    • Hi Sandy,

      I think you should add carbs first, then re-test before deciding what to do about supplemental hormones. Adding supplemental T3 on a VLC diet is counterproductive, it will create more adrenal stress and hypoglycemia. You need to give more carbs so that the hormones don’t have to do so much work.

  26. Hi Paul, I enjoyed the first edition, and now I am looking forward to reading the second! I would be particularly interested in a post on allergies/sinusitis/asthma (they all seem to be linked and cause a huge amount of misery for a lot of people). My 3 year old suffers from pretty bad hay fever during spring and fall, which results in a lot of swelling and inflammation in her sinuses. The big problem is that this often results in a sinus infections or conjunctivitis. If you could solve that one, a lot of people would be grateful!

    • Hi John,

      Have you tested her vitamin D levels and does she eat A and K2 rich foods? I would try supplementing her with K2 and making sure he D is optimal as a first step. Also, have her eat a few egg yolks a day and liver on occasion.

  27. Paul, when will the AHS 2012 conference videos be posted (and where?)

    • Hi catherine,

      It will be a while, they have a tremendous amount of editing to do. They are planning to splice in ppt slides into the video of each talk (the video camera just focused on the speaker).

  28. We talk a lot about longevity, but very little is mentioned regarding fertility. I’m sure a lot of readers would be keen to not just live long but also stay fertile for a long as possible.

    Increasing carb intake helps fertility (potatoes, yams, sweet potatoes, white rice, buckwheat etc) whereas eating low carb (for young people) is equivalent to starvation. It increases cortisol, lowers thyroid function and in some women, stops their menstrual cycle. The body think’s you’re starving and unable to bear offspring. Plus low carbing seems to cause so much mineral loss from the body, I don’t think that’s a good thing (especially for the heart).

    The Japanese eat lots of white rice, as do the Chinese and other LEAN people in Asian countries, Pacific islanders eat lots of starchy root tubers, pre-columbian Mexicans (who were lean) ate corn (as did the American Indians), the French love their bread and Italians love their pasta. I mean these aren’t cultures dying from obesity despite high carb intake. Each culture varies in longevity, and on average, they are mostly lean compared to Americans on SAD.

    I think carbs are safe as long as calories consumed aren’t over the top, that most of the food isn’t processed and refined vegetable oil use is avoided.

  29. Syl- Have you read PHD.

    • I sure did, but I noticed that on this blog and in the book, the emphasis is on longevity, so while carbs are recommended, the amount isn’t very high (which is important for active folks, young women, people who work in mentally taxing jobs and athletes), it mentioned very little on fertility.

      I just wish there’d be more articles on fertility and carbs.

  30. Hello Paul,

    Wanted you to know that I appreciate your book. Maybe I’ll get the revised edition.

    I think it is interesting that you have that PhD in physics. This tells me that you have an edge, and that is why I am interested in what you say, even though nutrition wasn’t your original field.

    I just hated the two research methodology courses I took in grad school. But I think most scientists would be able to go cross-disciplinary very well. They can see where the gaps in research lie, and they enjoy interpreting data, and those abilities (which I lack) are something to be grateful for today.

    I see this discussion turned to longevity. I wish people would understand that there is a spiritual aspect to longevity (see the 5th commandment in Exodus 20). Also, the ability to forgive and not hold grudges goes a long way toward emotional and physical health.

    Love your work!

  31. This is a brilliant summary of the arguments.
    We have people who live to the current maximum, the supercentenarians.
    If we assume that eating or taking something they didn’t, or not eating something they did, will cause us to live longer, we’re dreaming.
    We should eat for health and happiness. Longevity is more likely that way, but it’s the wrong goal to put first.

    • I totally agree. Stressing out over what you’re eating, or how low you need to reduce your carbs or if you eat a piece of cake it’s going to shorten your life is probably going to shorten your life purely because you’re stressing!

  32. Paul:

    T’was great chatting with you at AHS. I haven’t read through all comments and I’m sure something along these lines have been said but I attended that panel and while I thought Jimmy did a decent impartial job given his disclosed bias, I just thought you and Chris Kresser really came off way more reasonable, making much more sense and even, gasp! common sense.

    And c’mon. For an average person, 30% of calories is 150-200g real food starches per day, still pretty low by SAD standards.

    Hopefully, one day, just saying that there’s a big difference between a sweet potato and a Big Gulp will be enough. End of debate.

    • Thanks, Richard. Sweet potato over Big Gulp is a good start. It doesn’t end all debate though!

      • “It doesn’t end all debate though.”

        Darn. I was trying to put us all out of business in one sentence. What, no takers ❓

        Be well, Paul. “Paper thin chicken soup” (recipe on my blog) on the stove. Last night, we went to sushi (yea, I ate the rice….) and I always have miso soup (i lived in Japan for 5 years) because of how it’s like the most amazing energy drink for me. Guess what I did when I got home? Went immediately to your blog and searched. “if anyone has a quality miso soup recipe, it has to be Paul and Sou”. I’m on it. Next week for sure.

  33. Paul, can I ask how much of this is based on good evidence and how much is speculation and extrapolation from from limited evidence base?

    The reason I’m asking is that I’m dealing with acne patients, but I suppose this applies to other conditions also. Adherence to dietary advice is of course linked to how practical that advice is. The harder the advice, the less people follow it. That’s why I’m reluctant to offer advice that’s too restrictive without good evidence.

    I know that carbohydrate restriction is good for acne, lowers insulin, IGF-1 and all the good stuff. I’m currently thinking 40-50% of calories as a good target for carbohydrates. That’s why I’m interested on what you based the 30% recommendation on.

    Your argument that in levels above 30% carbs are converted into fat doesn’t strike as too convincing. As others have noted, it could be just evolution allowing us to survive with widely varying food supply.

    Thanks for your thoughts!

    • Hi Seppo,

      We present a large number of evolutionary arguments for the optimal carb intake, and some biological ones mostly related to CVD risk, in the new edition of our book.

      As for how convincing it is, I don’t expect it to persuade everyone, but it is persuasive to me and I think no other carb intake is as well supported. The skeptical case would be that there may be little harm to different carb intakes, rather than that some other carb intake is superior.

  34. Hello Paul,

    Thanks for the response. Although you might have tackled this in the new PHD edition I thought I would still ask.

    I think many would like to know when eating LC and VLC would be a good idea. I also think more of us are understanding VLC,LC eating can be therapeutic, but I think where many are still less clear on is when it is appropriate and when is it not.

    For example, its more obvious to treat conditions by eating LC and VLC will probably be more appropriate for those that are overweight,and treating epilepsy, etc, all in their own particular and temporary time frames.

    But what about other conditions and concerns such as autism and cancer-prevention and cancer-treatment which are less obvious that eating LC and VLC can be useful in assisting.

    I believe many of your readers would appreciate a post on when LC and VLC are usually beneficial and when they are usually counterproductive.


    Henry Duran

    • Hi Henry,

      I think going slightly lower carb may be beneficial for diabetes (eg 30% to 20% carb).

      I think going lower carb than that, eg 10%, is only desirable in a ketogenic diet, which is mainly therapeutic for neurological conditions, possibly for some infections.

      Cancer – I would go ketogenic for brain cancer, but do intermittent fasting with normal carbs for others.

      Autism – I would give a ketogenic diet a try, but it is unproven.

      Thanks, that is a good post idea.

      • Hello Paul,

        In regards to cancer, would you recommend a paleo version of WIlliam Li’s anti-angiogenic foods?




        • Hi Henry,

          We did two posts on anti-cancer dieting. Try the cancer category or search on cancer in the Google custom search box.

        • Hi Paul,

          Did you ever write a post on this topic (i.e. which conditions can potentially benefit from a LC/VLC approach)?

          I am currently trying to understand the best ways to proceed for my family. Our son’s autism-spectrum style symptoms were hugely impacted, in a positive way, by (among many other dietary interventions) lower-carb eating. But I begin to be swayed by the possibility that he could benefit from higher carbohydrate intake now, four years after we changed our diet (initially high-carb/low-fat vegetarian).

          I would love to read anything further that you’ve got on this topic.


  35. I think part of the problem in using traditional diets to guide our current eating habits is that groups like the Okinawans never grew up for decades eating the “crap” we do in industrial cultures. I often wonder if most of the health benefits people see on LC/VLC style diets are only applicable because it’s a grand shift in the opposite direction of the high sugar SAD. And hence LC/VLC puts our bodies in a position to fight against the typical diseases our previous diet has set us up for. Take someone who has been eating SAD for 2-5+ decades (i.e. most of your readers) and put them on a diet severely restricting overall carbs, fructose, gluten, vegetable oils and it’s no surprise when they see huge improvements in their metabolism, blood sugar, weight management, and disease susceptibility. But would a LC/VLC diet improve the longevity of a traditional person who never “broke” their metabolism, blood sugar, weight management, etc. to begin with? If we stepped back in time and took a super centenarian Okinawan at age 30 and fed him a LC/VLC paleo diet instead of rice would there be any difference in his overall longevity than if he continued eating 80% starches? It’s an interesting discussion.

    • Yes I’d be really curious to find that out too.

      Or if the Kitavans goes on a LC/VLC diet! That would be an interesting result! Because these people are not in any diseased states, I wonder if LC/VLC will cause any problems for them.

      Most readers aren’t autistic or suffering from seizures. The main people who would benefit from LC/VLC are diabetics. But many readers just want to be healthier (who don’t have any conditions), so what might be beneficial for a diabetic might not be for someone with normal glucose metabolism.

  36. Seppo,
    Great blog you have, and I know the disease of acne very well, having had it for more than 40 years. In fact, my therapeutic experience with Accutane (which happened in 1983) almost exactly paralleled yours.

    I believe some of us just inherit weak, defective follicles. Your neighbor down the street may have a weak respiratory system, making them very susceptible to influenza or bronchitis.

    I don’t believe in extremes either when it comes to diet. I mean, I found great help years ago by simply drinking 1 T. of fresh lemon juice each morning in a glass of water. Nothing could be simpler, and I can’t tell you why it helped. Some say it is beneficial for the liver.

    I also believe, based on my n=1 experience, and as I’m 60 years old now, that your acne will get noticeably better once you’ve accomplished most of your life goals. Because by that time, you quit caring about the kind of impression you make on people. This interesting fact seems to coincide with the end of the reproductive years, at least for women. I do believe that acne is a disease of the reproductive years, by the way, and as my former, funny, witty dermatologist said to me, “Absolutely correct! You never see acne in eunuchs!” 😀

    • Sherry,

      Thanks for your kind words. Happy to hear you found my blog useful. Yes, it’s true that genetics plays a big role in acne. It makes the skin far more sensitive to hormones and causes the immune system to overreact.

      I’m also not a big fan of overtly restrictive diets. But I know carbohydrate restriction works, and that’s why I want to check if there’s a good reason to limit carbohydrates to 30% of total calories.

      As you must know, people with acne can get very desperate and frustrated. So I’ll do my best to find anything that gives them an edge over it.

      Yes, it’s a disease of reproductive years. Not sure if your dermatologist was serious, but there are observations in medical journals that castrated men don’t get acne!

      • Kitavans (who live on their traditional diet) have no acne and they eat tubers and other carbs. So maybe it’s not carbs that cause acne?

        There must be something in the Western diet that causes acne. Perhaps it’s dairy, or sugar or vegetable oils/trans fat.

        • Syl, adult acne comes down to 3 things: genes, hormones and inflammation. One of the main problems with Western diet is that it breaks glucose metabolism, basically it creates insulin resistance. High insulin and IGF-1 levels translate almost directly to higher sebum production on the skin. Those hormones also make the skin even more sensitive to androgen hormones. Androgens also increase the sensitivity of the skin immune system, and that causes a lot of inflammation in the skin.

          Gut issues are another consequence of Western diet and lifestyle. Acne and skin patients have higher prevalance of gut issues. This has been known since the 50s! There’s also a handful of studies that show improvements in acne when gut issues are treated with probiotics.

          That’s the ‘in the nutshell’ explanation of how Western diet and lifestyle causes acne.

          So it’s not carbohydrates per se that are the problem, but rather our weakened ability to metabolize them.

          • Seppo,

            So how do you go about strengthening the ability to metabolize carb’s in clients with acne?


            Kris Cleary

          • Kris,

            Nothing beyond the usual stuff, like exercise, lose fat, diet to improve insulin resistance and reduce inflammation, stress and sleep. I’m not sure there’s much to do beyond those. There’s some talk about supplements and herbs, like cinnamon, and how they support glucose metabolism. But that’s more hype than reality. Studies have shown very limited benefits from those.

  37. I have a question about supplements, melatonin in particular. Your site says:•An important sleep hormone, deficient in many brain diseases, has antimicrobial activity
    •Take just before bedtime
    •To avoid early waking, combine 5 mg time-release with 1 mg sublingual

    This is the only hormone you recommend taking, is it safe to continue indefinitely? if I find it helps me sleep, (I take this one, http://www.naturemade.com/products/sleep/nature-made-sleep-natural-sleep-aid – it has L-Theanine, chamomile, passion flower extracts) what are the issues with continuing to take it for too long? Is it true, as mark sisson says, that it can be dangerous because the body will produce even less? http://www.marksdailyapple.com/before-you-close-your-eyes-make-sure-theyre-open/

    Your diet has truly helped me be sane again. I was feeling so run down, and guilty for eating rice, potatoes, and sweet potatoes. (beware the medicine of the mind I guess)

    And furthermore, I think the intermittent fasting has helped sleep immensely. Although, don’t know if you’ve heard of it, Martin Berkhan (the site founder of Leangains, devoted to IF, more for fitness purposes) recommends 10 hours for women of eating, 14 hours of fasting starting out. , I think this was true for me – it was too hard to make the jump to 8 hours of fasting. It’s just his personal experience with clients and mine too. I think his site might have some research on why this is (and I also found his article on breakfast making one hungry interesting). It might be something to note for any future updates of your book!

    Thanks for everything.

    • Hi lynh,

      I’m not aware of long-term harms from melatonin supplementation. Yes, if you take too much it will downregulate natural production. The solution is to reduce the dose.

      I’m glad you’re doing well! Thanks for the info from Martin.

  38. PS Good luck with your copy editing!

  39. Seppo,
    More needed about the acne discussion.

    Care must be taken to differentiate between oily skin and acne. You need oily skin to have acne (except in cases of acne rosacea or some weird manifestations of whiteheads), but oily skin doesn’t necessarily result in acne. This has always interested me.

    The ONLY time in my adult life when I had anything approaching “normal” feeling skin was when I was eating low fat, high carb. But not just any low fat diet. I made sure that I was eating clean, with no processed foods and very little sugar. I ate a lot of brown rice and white potatoes. LOTS. In 4 complete meals per day, to avoid hunger. This is the traditional weight lifters diet (most serious weight lifters would eat 5 meals). When I was eating this way (for about a year), I would have great, normal skin moisture and texture. Finally, about 3:30 PM, I’d notice a very minute amount of oil. My conclusion is that low fat equals more normal skin.

    Make no mistake, however. I don’t eat low-fat now. Just the opposite. I eat the Perfect Health Diet. I’ve still got oily skin, but my acne is under control due to my diet and use of Retin-A. It’s a good trade-off.

    I also have to say this: when people ask me, did the high-fat, clean, non-processed, wheat-free diet I’m consuming now help my acne, I tell them, “I don’t know. I’m not going to stop my topical skin treatments to see what would happen.”

    • Sherry,

      Yes, there are always exceptions to such generalizations. Reduced carbohydrate intake works for many people, but I’ve also heard a lot of success stories with the low-fat approach. There’s also plenty of research showing improvements in insulin resistance, insulin and blood glucose metabolism with low-fat diets.

      I don’t have statistics on the issue, but if you would ask me to quess I would say lowered carb intake is more effective.

      One thing that may explain this is the mild insulin resistance that seems to follow increased fat intake. That’s one of my hesitations for going too low carb.

      It’s true that oily skin and acne don’t always happen together. Often they do, but not always. Oily skin creates ideal conditions for acne to form, but it doesn’t cause acne as such. For acne to form there needs to be inflammation in the skin. But if you don’t have gut issues or other sources of systemic inflammation and take good care of your skin externally, then there’s not much oxidative stress on the skin.

      The botton line is that acne is darn complicated, and there aren’t any one-size-fits-all solutions.

    • all this talk of oily skin has caught my interest.
      My skin has always been somewhere between dry & very dry (too dry). (i have never had acne).
      I would like my skin to become more oily…
      …Any Tips on things i could try to achieve this?

      Probably unrelated, but another ‘symptom’ i have had for as long as i can remember, is a chronic runny nose.
      My nose is not congested & i breath through my nose fine (not through my mouth), it just runs quite a lot (clear liquid). so i always carry tissues & clear/blow my nose a lot.

      I have wondered if may be there is some link/relationship between the runny nose & dry skin? may be if i can ‘fix’ one i’ll fix them both.

      • Darrin,

        Dry skin usually means there’s a problem with the skin barrier function. Basically the skin allows too much moisture to escape. There can be several reasons for it, such as:

        – Using soap to clean your skin. Soap neutralizes the protective acid mantle. One should use pH-balanced products, especially on the facial skin.
        – Harsh chemicals in cleanser. Some chemicals are just too much for the skin. They may cause inflammation and damage to the skin barrier function.
        – Long, hot water showers.
        – Anything else that irritates the skin.

        The solution is usually quite simple. Remove what irritates the skin and use moisturizer. There’s a more detailed dry skin article on my website.

      • Darrin, your constantly running nose with clear liquid sounds like classic vasomotor rhinitis. Has any doctor every told you that you have this? I have it myself, but rarely with a runny nose. It can either run wet or dry in a patient. I have had doctors examine me and tell me that my turbinates look red and swollen, even though I can breathe OK.

        By the way, allergists typically will tell you that you have vasomotor rhinitis, if you don’t have a reaction to the approximately 75 substances they test you for.

        Vasomotor rhinitis is thought to involve a nerve imbalance in the nose. Recent research links VMR with migraine.

        • thx Sherry, from memory, i think i actually diagnosed myself with vasomotor rhinitis, & my doctor agreed. its all year round thing for me, not affected by the seasons.
          i was tested for allergies, all negative.

          i tried a few different nasal sprays in the past. but they are just temporary solutions & not that good anyway.

          the good news is that my nose does not run in my sleep, at least externally anyway, may be its running down my throat…yuk

          • I’ve had this problem lots in my life, but these things seem to have helped – in approximate order of usefulness, immediacy of benefit, or ease of application.
            I haven’t had it all year.
            – Probiotics, especially L. Rhamnosus LGG plus B. Bifidus
            – grape seed extract: 200mg OPCs 2x daily before meals
            – avoiding all dairy products including cheese and yoghurt for a time; including “milk solids” in chocolate
            – avoiding grains and dried pulses, including soy lecithin in chocolate.
            – a short period of all-meat diet
            – treating attacks with a glass of wine. I don’t usually drink, and found the reaction dried up the nose for a day or two.
            – if all else fails, inhale marijuana smoke and breath it out once through each nostril, trying not to get high. I found I could do this in emergencies without getting stoned, and it had a very drying effect. But the effect only lasts an hour or two.

          • thx George,
            i’ll go hunting for some Rhamnosus GG (aka LGG) to start with & see how that goes.
            I have taken L. Rhamnosus in the past, but not the GG strain.

          • I think there is a synergy with the probiotics, the grape seed extract, and milk avoidance.
            I don’t need to avoid milk now. And I think it was connected with after effects of colds and flus and with low vitamin D and A due to winter and infections…
            And bad gut due to grain and legume toxins…
            Complicated, but not impossible to solve.

          • i’m a bit wary of grape seed extract because it contains Resveratrol, a phytoestrogen, which could be Estrogenic and/or Anti-estrogenic. here’s one ref,

            so my thought process is that i do not go out of my way to consume things that may influence estrogen, esp if there’s a possibility of raising estrogen levels

          • Grape seed extract is very low in resveratrol, grape skin is much higher. It’s almost all OPCs which are similar to green tea, apple, berry or chocolate catechins.
            These 2 analyses found no resveratrol worth mentioning.
            I think it’s exaggerated nowadays to sell more GSE.
            I can’t stand resveratrol and wouldn’t use GSE if it had the same effect. I like GSE because it is so generic; it’s typical of the polyphenols that used to be common in prehistoric diets, it’s not a single isolated phytochemical, and it’s cheap.
            GSE seems to reduce conversion of androgen to estrogen – in cell cultures
            but I doubt this is significant at normal doses.

          • that’s good to know george. you right there is a lot of marketing hype around resveratrol.

            So now you’ve made me think of grape seed oil, is grape seed oil just diluted GSE. ie. GSE is concentrated grape seed oil.

          • No, GSE and grape seed oil are totally different. The oil is just a high-PUFA seed oil.
            The extract is the water-soluble astringent fraction of the seed.
            It can bind to casein and egg white, which may be part of its value in allergic disorders.

          • on the resveratrol subject, i’ve just seen that “resveratrol is potentially a remedy for (male) baldness”
            …yeah right


          • Well, if you rub it on your scalp, it probably won’t do any harm.
            Fo Ti and black sesame are the chinese remedies for hair loss or greying. Fo Ti contains a pterostilbene related to reveratrol, OPCs, is high in phospholipids. Sesame contains a ligand that elevates GLA levels at the expense of AA, which might well reduce PGD2.
            So the idea is not ludicrous, but a mixture of natural extracts might be more effective than pure resveratrol.

            Research carried out in 1989[3] found PGD2 is the primary mediator of vasodilation (the “niacin flush”) after ingestion of niacin (nicotinic acid).
            A 2012 research paper indicates a causal link between elevated levels of localized prostaglandin D2 and hair loss.[4] Applied topically, the research found PGD2 prevents hair growth, and mice that were genetically inclined to produce higher levels of PGD2 had inhibited hair growth. The paper suggested one of the receptors involved in production of PGD2, GPR44, would therefore be a therapeutic targets for androgenic alopecia in both men and women with hair loss and thinning.[5]

          • Hi Paul,

            What are your thoughts are grape seed extract. This George/Darrin discussion and the following comments on preventing macular degeneration and strengthing arteries caught my attention.

            Grapeseed extract contains polyphenols, also called flavonoids or catechins. These compounds strengthen the arteries, improve free radical destruction and even help to prevent macular degeneration and cataracts. Studies have also shown the important cancer-fighting potential of grapeseed extract, as well as the tremendous potential benefit to the heart. And recent studies have established that the extract can help to reduce inflammation.


          • Hi Mark,

            What the polyphenols do and when they are beneficial and when harmful I think is a complex topic. My personal resolution is to just eat normal, tasty plant foods and not supplement with plant extracts. I figure evolutionarily normal levels of plant phenols are the most likely to be beneficial.

          • I’d agree with that unless there is some clinical reason for trying supplements. Robb Wolf makes the case that the paleo diet contained many more polyphenols; but adding foods such as cocoa and spices, berries, green tea in the PDH also elevates intake of these.

      • Cutting down on wheat and sugar seemed to make my skin nicer…

        • Those things commonly aggravate acne. Wheat can cause sensitivity reactions and gut issues in some people. Sugar spikes insulin that makes hormonal acne go crazy. Good to keep both to minimum.

          • Seppo and others,

            How does the thyroid play into acne?

            I have been taking natural thyroid medication for a little while now and my acne has improved quite a lot. When I stopped taking it for a week or so I got a really bad breakout of acne on my back and chest. Back and chest acne apparently is a chief symptom of hormonal issues right?

            Kris Cleary

          • Kris, for me personally my skin’s somewhat-dryness improved a lot on PHD and when I started supplementing iodine it became silky smooth, almost glowing 🙂

            So chalk that one up to thyroid as well I think.

          • Kris,

            I have to say I don’t know. It regulates metabolism so maybe it can affect hormones or gut health and that way the skin also, but I’m not aware of any mechanism.

            All adult acne is hormonal to some degree or other.

          • Hi Kris,

            Yes, in myself I’ve noticed that the thyroid is the dominant factor controlling skin quality. Good thyroid, good skin.

            That’s probably my major lead in investigating acne & rosacea.

          • Ok thanks guys! I’m going to go read over Paul’s posts on the thyroid. I look forward to weening myself off natural thyroid med’s over time. =)

  40. Hi Paul
    What is your opinion on the standard recomendations regarding caloric intake based on age/activity level. I’m a fairly active 30 year old and the calculators I use suggest a caloric intake between 2600 and 3000 per day. Seems fine, just wondering what your take on their calculations is?

    Also, does one’s caloric source percentages change at all with these higher caloric levels, or is it still 20% carb, 15% pro, 65% fat even when consuming 3000 calories a day (ie 600 carb, 450 pro, 1950 fat)?

    Thanks for all your advice online and in your book.

    • Hi Thomas,

      I think 20-35% carb 15% protein is still a good rule.

      I wouldn’t trust those calculators. The number of calories you need depends on nutrient quality of the diet, body weight, and other parameters. Most people have excess weight and eat nutrient-poor diets, so they need more calories than you should.

      The key thing is to eat to appetite.

  41. george henderson

    Paul, about the idea that particular pathogens (and cancers) can exploit any diet: R. D. Feinman and E. J. Fine have a(n unpublished?) hypothesis that R.D. linked to in the comments in one of his posts – but where?
    The thesis was, that if a cancer evolved in a particular milieu – usually a high-carb milieu, these days – then drastically altering the terrain (in that case, by ketogenic dieting) would disadvantage the cancer. If it could not adapt it would die.
    This gave a rationale for understanding when to expect benefit from VLC and ketogenic diets in cancer.


    I am sure he will link you to the paper if you ask. I have his email but don’t want to put it here: I’ve send it in a message to the PHD Facebook.

    So – by extension of Fine and Fineman’s ideas – a pathogen that you developed on a ketogenic diet might be killed by glucose replacing ketones; a cancer or pathogen developed on a diet very low in polyphenolic food toxins might be killed by a switch to a raw food vegan diet – and so on.

    • It’s a plausible theory. Cancer is a rapidly evolving entity and it does adapt to the host environment, including the levels of energy substrates and hormones in the blood.

  42. george henderson

    Also look at this:

    Targeting insulin inhibition as a metabolic therapy in advanced cancer: A pilot safety and feasibility dietary trial in 10 patients
    Fine EJ, Segal-Isaacson CJ, Feinman RD, Herszkopf S, Romano MC, Tomuta N, Bontempo AF, Negassa A, Sparano JA.

    Eligible patients with advanced incurable cancers had a positive PET result, an Eastern Cooperative Oncology Group performance status of 0 to 2, normal organ function without diabetes or recent weight loss, and a body mass index of at least 20 kg/m(2). Insulin inhibition, effected by a supervised carbohydrate dietary restriction (5% of total kilocalories), was monitored for macronutrient intake, body weight, serum electrolytes, ?-hydroxybutyrate, insulin, and insulin-like growth factors-1 and -2. An FDG-PET scan was obtained at study entry and exit.
    Ten subjects completed 26 to 28 d of the study diet without associated unsafe adverse effects. Mean caloric intake decreased 35 ± 6% versus baseline, and weight decreased by a median of 4% (range 0.0-6.1%). In nine patients with prior rapid disease progression, five with stable disease or partial remission on PET scan after the diet exhibited a three-fold higher dietary ketosis than those with continued progressive disease (n = 4, P = 0.018). Caloric intake (P = 0.65) and weight loss (P = 0.45) did not differ in those with stable disease or partial remission versus progressive disease. Ketosis was associated inversely with serum insulin levels (P = 0.03).

    Are these all brain cancers? Maybe not, in which case the full-text might be worth a look.

  43. R. D. Feinman has just posted a link to the full-text of Fine’s ketogenic diet cancer trial (around 8% carbs). One of the proff’s best posts this.

  44. Here is the breakdown of cancers in the EJ Fine trial; not a brain tumour among them: so a ketogenic diet does seem to have a wider utility in cancer treatment.

    Patient Age Sex Cancer Year Prior chemo

    1 61 F breast 4 5
    2 53 F fallopian tube 5 5
    3 73 F breast 14 0
    4 70 F colorectum 5 4
    5 69 M lung 5 5
    6 72 M esophagus 2 6
    7 52 F colorectum 5 4
    8 61 M colorectum 6 6
    9 64 F ovary 5 10
    10 54 F lung 4 8

    • One thing I haven’t looked into in these cancer trials is the quality of the ketogenic diets. I diet made “ketogenic” with soybean oil would be very bad for cancer. Possibly diet quality may account for the divergent results.

  45. Yes, improving these diets would be a worthwhile thing.
    I am thinking that what this research may demonstrate in the long term is that whether a cancer can run on sugar or ketones or protein or fat is less important than the effects of growth factors such as insulin on the tumour; it does not grow merely because it has food, but because it is being prompted to grow by distorted growth signals to which it may be hypersensitive, and these signals are sensitive to macronutrient ratios and amounts…
    If the growth factors are important then we should expect less cancer on ketogenic diets, even after long-term adaptation.

  46. The Safe Starches Panel from AHS 2012 | Perfect Health Diet - pingback on November 6, 2012 at 5:48 pm
  47. Hey Paul,

    Been eating PHD style for a couple weeks now and had a quick question about safe starches. I like to enjoy a “cheat day” once a week.. rather than go outside of the PHD rules I am trying to stay within them but enjoy a treat. Tapioca or rice syrup is great and I have used it in homemade ice cream and chocolate.. is there a limit to how many safe starch calories should come from these syrups in a day? or if one day a week I ate 4-500 calories as tapioca syrup would that be fine is that was the extent of my “safe starch” content.. with the exception of a lack of minerals/vitamins and fibre.. does the body essentially react the same way to the syrup calories as it would the starch from these potatoes or rice?

    • Hi BS,

      There’s no problem eating that many glucose calories in a day, so the only defect of that approach is the things you’re missing by not eating whole foods — micronutrients, fiber, and so on — but it’s no big deal to miss those occasionally as a “cheat day.”

      So I think that’s a fine thing to do.

      Syrups are not a perfect equivalent to foods — glycemic index is higher, nutrition and water content lower — but the defects are relatively minor if they’re not a routine thing.

      • Thanks Paul, It’s pretty unlikely I would consume 500 calories from syrup in a day but it’s nice to know if I was really craving sweets I could have something like that. I am more like to use 100 calories a day as syrup in things like homemade chocolate or salad dressings and use the rest as regular starches. I use natural stevia some but since there isn’t much long evidence for larger amounts of stevia I try not to go to crazy with it.

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